Steam power plant



Oct. 15, 1929.

- C. A. FRENCH STEAM POWER PLANT Filed May 26, 1923 2l smeris-sheet 1" ooooooooooooooo ooooooooooo'o'ooooo Y oooooqooooooqoo o oooooooooocfoo oo ooooooooooo O Q Q Q N h O Q Q o l volooooocioooooooao oooooooooooooooo oooooooooooooo o OOooQcaooooocaol oo'ooooooooooooo. Q

c. A. FRENCH Oct.- 15, 1929.

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O O IO O Oy oooo'oo o o o 000000000 ooooooooooooooo ooooooooooooooooo ooooooooooooooo ooooooooooo'oooo ooooooooooooooooo Patented Oct. 15, 1929 .uNrll-:Dy STATES l PATENT lorifice CHARLES A. FRENCH, OF COLUMBUS, OHIO,'ASSIGNOR TO FARMERS NATIONAL BANK.,

OF GREENVILLE, OHIO, A CORPORATION OF OHIO, TRUSTEE STEAM POWER PLANT v Application filed May 26,

This invention relates to steam power plants and particularly to improvements in automotive steam power plants of the type shown in my (3o-pending application Serial 5 Number 592,695.

In the application above re'ierred to, I have pointed out the difiicu-lties heretofore `encountered in automotive steam power plants and the necessity for reliable automatic control of the quantity of Water (liquid and steam) in active circulation in the system,r and disclosed a closed system in which a fixed quantity of Water is circulated continuously provided with automatic means for making up of the slight quantity of water that is unavoidably lost by leakage.

rthe present invention. relates to the same type of power plant and provides a' thermostatically actuated valve, the yoperation of 2o which is controlled by the amount of water in the system, for directly controlling the admission of make up Water.

Referring to the drawings- Fig. 1 is a diagramn'iatic representation of 25 a steam power plantembodying my improvements;

Fig. 2 is an enlarged view of'the'thermostatic valve; and y Figs. 3 and 4 are similar views of a modified --constructien.

Exhaust steam from the pipe l0 enters the condenser 11, from which the condensed water is withdrawn throughl pipe 12 by a pump 13 (preferably of the rotary type) and discharged through pipe '14 into the hot Well and skimmer 15 from which the air escapes 'through vents 16 and the excess of oil is drawn off through the overilow pipe 17, vwhile -the Water rises between the batlles 18, 19 and overflows into chamber 2() of the hot Well,` from Where it enters the intake pipe 21 of the feed. pump 22. The pump has intake and discharge valves 23 and 24, the intake valve normally closing on the discharge stroke ofthe pump, but being held open by a push rod 25 whenthe head of Water in thehot Well and intake pipe 21 is insuiicient yto hold the diaphragm 26 depressed against the pressure `of the spring 27, so that tliepump will not discharge Water to the boiler but will return it 192e. seran No. 641,737.

to the intake pipe, thereby preventing all the y Water from being Withdrawn from the hot Well and the pumps becoming air bound.l

torI 30, and superheater 31 enclosed within a shell 32 to which heat is su} plied from a' burner 33, the hot gases flowing downward and radially outward through the boiler and being discharged downward through the annular flue 34.

As -shown in the drawing, the preheater, evaporator and superheater arel termed from a plurality of concentric banks of coils, the Water from the feed pump entering the outer coil of the preheater in the coolest part et the boiler and advancing progressively through the coils toward the center or hottest part of the boiler. Hot water from the preheater euters` the outer evaporator. coil through an ejector 35 where it picks up additional Water from the storage drum 3G. Wret steam or a mixture of steam and Water from the evaporator 30 is discharged tangentially into the storage drum from pipe 37, the water sepa-- rated by centrifugal action accumulating in the drum While the dry steam is taken from the top of the drum by the dry steam pipe 38 leading to the superheater 31. Steam from the superheater lea-ves the boiler through the steam main 39 leading to the main engine or other prime mover and the auxiliary engine' 44.

" The Water accumulating in the storage drum is returned to the evaporator through the pipe 40 and ejector 35 as previously described. An auxiliary circulating pump 41 is operated by shock from the feed pump 22 and is connected in. the pipe 40 to assist in the circulation through the evaporator. A free piston or plunger 42 in this pump is moved in lone direction or on its discharge stroke by shock from the feed pump with-the delivery side of which it is in direct communication.v The plunger is-moved in the opposite direction or `on its intake stroke by a spring f3 during theinterval that the pump 22 is making its intake stroke. It will be understood that the pump 41 and ejector 35 mutually cooperate to produce the same result and that either may be used without the other in many instances.

An auxiliary bngine 44, which is preferably operated by steam from the boiler, drives the pumps 13 and 22 and also an auxiliary feed pump 45 which normally draws in water from a reservoir 46 and returns it thereto through pipe 47, 48, valve 49, and pipe'50. The valve 49 is normally open so that the pump 45 merely circulates water through the parts just described, but if the amont of water in circulation through the system falls below normal, the valve 49 is closed by thermostatic means and the pump 45 then discharges through vthe check valve 51 into the feed pipe 28 until the quantity of water in the system is restored to normal.

The valve 49 is connected to the expanding element 52 of a thermostat mounted on the storage drum 36. The expansion element is hollow and its lower end is rigidly connected at 53 to the drum below the normal water level while its upper end is connected by a tube 54 to the drum above the normal water level, thetube 54 being suiiiciently flexible to permit expansion of the thermostat. The

valve and movable end of the expansion ele-` ment are guided by rods 55, 56 carrying springs 57, 58 against the pressure of which the valve may move if the expansion element continues to expand after the valve is closed, as is clearly shown in Fig. 2.

When the system is operating under normal conditions and the pump 22 is returning water to the boiler as fast as steam is being generated, the level of the water in the storage drum is high enough to cover the expansion element and the valve 49 is held open. But if the supply of water fails or the amountin circulation decreases through leakage or for any reason, the level in the drum will fall exposing the expansion element to the steam so that it expands and closes the valve 49. The auxiliary pump then delivers water to the boiler until the level in the drum is restored, after which the thermostat vcontracts and opens the yvalve 49.

In Figs. 3 and 4 I `have shown a modified form of my invention in which the auxiliary feed pump is dispensed with and the makeup water is supplied to the hot well, the valve controlling the supply of makeup water being 'closed normally. In these figures, many of the parts are the same as in Figs. l and 2 and therefore are designated by the same reference characters and will not be described in detail.

valve is connected to the free end of the expansion element 65, the fixed end of the expansion element being mounted in the frame 66 by which it is connected through the nipple 67 f to the drum 36 below the normal water line. The valve and movable end of the expansion element are supported on the guides 67, 68 which carry springs 69, 70 offering a yieldable resistance to movement of the valve caused by further contraction of the thermostat after the valve is closed.. The upper end of the thermostat 1s connected by a slightly yieldable tube 71 to the drum above the water line.

When 'the system contains the normal amount of water in circulation by the feed pump, the level in the drum 36 will be high enough to cover the thermostat, which will be relatlvely cool, as the water is not in circulation, and hold the valve 64 seated so that no water will flow from the reservoir 60 tothe hot well. But, when for any reason the water level in the drum falls,'the expansion element will be subjected to the temperature of the steam and, expanding, will open the valve 62 so that water will flow to the hot well until normal operating conditions are restored.

The power'plant just described is of the closed type, in which a relatively lixed quantity ofwater is being continuously circulated, only enough make-up water being added from time to time to replace unavoidable l. losses. The water is supplied to the boiler by the feed pump 22 which is driven at 100 V lconstant spee'd from the auxiliary engine and is of sufcient capacity. to take care of the, maximumload on the boiler. The burner 33 is of the'hitand miss type, that is, it is either burning at full capacity or entirely lboiler carrying its maximum load, steam will be generated at 500 pounds pressure per square inch and 300 to 400 degrees superheat. Since all of the steam is condensed and re` turned to the hot well, the pump 22 supplies the maximum amount of water when the steam consumption is a maximum and sup .plies the `minimum amount of water when the steam consumption is a minimum, and for all intermediate loads .the amount of water pumped is proportional thereto. However, if the-water in the hot well reaches a certain low level the pump will miss until the water raises suiiiciently in the hot well. The amount of water going through the preheatert coils v29 `is therefore always equal to the 125 I amount of steam being generated. The water coming from the preheater through the ej ector induces a quantity of water from the storage drum which, together with the water from the impulse pump (if used) is about three times the amount of waterV evaporated. The pipe 37 therefore discharges a mixture y into the drum of to 30 per cent steam and to 75 per cent water. A supply of water is always assured in the drum and the circulation through the coils is at a very high velocity because of the amount of water han-V manded, the boiler is most eiiicient at its maX- imum load. When the power plant is operating under light loads, the pump 22 will not deliver water to the preheater at every stroke because the amount of water being returned to the hot well from the condenser is small. The rapidity oi': circulation in the preheater will therefore fall ofi" and the amount of water picked up from the drum by the ejector will decrease. The rapidity of circulation in the preheater will therefore fall olf and as the re will only be burning for a small portion of the time the evaporating coils will till by gravity from the drum when the lire is not burning. When the demand for steam is small, naturally vaporization of a very small quantity of water in the evaporating coil will suflice to restore the pressure to n'ormal. vWhen the demand for steam is' small it is not important that there should be a rapid circulation of water in the evaporating coils, as the fire can only be on a very short space of time, never in any case suicient to produce superheat in these coils.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. In a steam power plant, of a boiler having a storage drum in whic a reserve of hot water is maintained, a hot well, means for supplying water thereto, a

ump vcontrolled by the'water level in the iiot well for supplying water to the boiler the quantity in the drum is less than a predetermined amount.

3. In a steam power plant of the type in which a quantity 4of water is continuously circulated and alternately vapori'zed and condensed, the combination of a boiler, a hot. water storage drum, a conductor connecting the drum'with the boiler, a feed water pump, means for returning water to the pump at substantially the same rate that steam is taken from the boiler and means controlled by the amount of water in the drum for delivering additional water to the boiler when the amount returned to the pump is less than the steam taken from the boiler.

Signed at Columbus, Ohio, this 24th day of May, 1923.

CHARLES A. FRENCH.

the combination and drum, and means controlled by the water level in the drum for supplying additional water to the boiler when the supply in the hot Well fails.

2; In a steam power plant, the combination of a boiler, a condenser, a Jeed pump, control means whereby the pump supplies 'water from said condenser to the boiler at substantially the same rate'that steam is being used, a water reservoir, a hot water storage drum, a conductor connecting the drum with the boiler and means controlled by the quantity of water in the drum to supply additional water to the boiler from said reservoir when 

